• Journal of Power Electronics
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• 제17권4호
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• pp.1109-1116
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• 2017

Wireless power transfer (WPT) technology has the advantages of intelligence and facilitation. This paper designs a WPT system applied to battery charging and provides a strategy which switches from the constant current (CC) charging mode to constant voltage (CV) charging mode. The LCL-LCL topology is used to realize the CC output, while the LCL-S (series compensation) topology is used to realize the CV output. The main factor affecting the output characteristics is extracted by analyzing the two topologies above. Based on the main factor, this paper puts forward a modified way to design the system. In addition, on-line monitors for the battery and switches are placed at receiving side, which avoids the need for introducing an information interaction module into the system. Therefore, the complexity of the controlling system is reduced. Finally, simulation and experimental analyses are carried out to verify the correctness of the compound topologies.

• 한국항행학회논문지
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• 제21권5호
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• pp.501-507
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• 2017

전자회로에서 부하가 제너다이오드일 경우, 입력전압에 의해 부하의 전류를 제어하고자 할 때 제너다이오드의 항복전압 특성에 따라 제어하고자 하는 출력전류가 변하기 때문에 기존의 전압제어 전류 생성 방법을 적용할 수 없다. 이 논문에서는 입력전압을 이용하여 정격치보다 큰 전류를 제너다이오드에 인가하여 부품의 수명시험을 할 때, 제너다이오드가 경년열화에 의하여 항복전압의 특성이 변하여 부하전압이 달라져도 이에 관계없이 동일한 전류를 낼 수 있는 회로를 개발하였다. 이 방법으로 구성된 회로를 실증하기 위해 각 블럭의 부품 값을 적용하고 시뮬레이션 하여 입력전압으로 출력전류를 선형적으로 제어하는 결과를 확인하였다. 결과에 의하면 우리가 측정하고자 하는 항복전압 이상의 입력전압에 대해서 출력전류가 선형적으로 변하며 제너다이오드의 경년열화에 의한 항복전압의 변화와 관계없이 일정한 전류가 흐르는 것을 확인하였다.

• Journal of Electrical Engineering and Technology
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• 제10권1호
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• pp.216-226
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• 2015

The neutral beam injection generate ultra-high temperature energy in the tokamak of nuclear fusion. The neutral beam injection make up arc power supply, filament power supply and acceleration & deceleration power supply. The arc power supply has characteristics of low voltage and high current. Arc power supply generate arc through constant output of voltage and current. So this paper proposed suitable buck converter for low voltage and high current. The proposed buck converter used parallel switch because it can be increased capacity and decrease conduction loss. When an arc generated, the neutral beam injection chamber occur high voltage. And it will break output capacitor of buck converter. Therefore the output capacitor was removed in the proposed converter. Thus the proposed converter should be designed for the characteristics of low voltage and high current. Also, the arc power supply should be guaranteed for system stability. The proposed parallel buck converter enables the system stability of the divided low output voltage and high current. The proposed converter with constant output be the most important design of the output inductor. In this paper, designed arc power supply verified operation of system and stability through simulation and prototype. After it is applied to the 288[kW] arc power supply for neutral beam injection.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2012년도 전력전자학술대회 논문집
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• pp.242-243
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• 2012

In this paper, 200 W power supply for LED driver has been designed, analyzed, simulated and tested. Input AC voltage of 100VAC-240VAC was converted to DC voltage by high power factor converter. Output voltage was controlled, and output current was controlled by constant current when output current was reached to LED maximum rated current. By simulation and experimental test, voltage and current control and high power factor characteristics are verified.

• 전력전자학회논문지
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• 제25권5호
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• pp.420-423
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• 2020

This study proposes an indirect constant voltage control algorithm for hybrid solid-state transformers (HSSTs) by using primary side information. Considering the structure of HSSTs, measuring voltage and current information on the primary side of a transformer is necessary to control the converter and inverter of the power converter. The secondary side output voltage is measured to apply the conventional secondary side constant voltage control algorithm, and thus, the digital control board requires the same rated insulation voltage as that of the transformer. To solve this problem, the secondary voltage of the transformer obtained from the tap voltage is used. Moreover, output voltage decreases as load increases because the proposed indirect constant voltage control scheme does not consider the cable impedance between the secondary output terminal and the load. This study also proposes a technique for compensating the secondary output voltage by using the primary current of the transformer and the resistance value of the cable. An experiment is conducted using a scale-down HSST prototype consisting of a 660 V/220 V tap transformer. The problem of the proposed indirect constant voltage control strategy and the improvement effect due to the application of the compensation method are compared using the derived experimental results.

• 전자공학회논문지
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• 제54권2호
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• pp.133-138
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• 2017

본 논문은 RC 시정수 회로를 이용하여 지터 특성을 개선한 위상고정루프의 구조를 제안하였다. RC 시정수 회로에서는 루프 필터 전압이 작은 시정수와 큰 시정수 값을 가지는 회로를 통과하여 비교기로 전달된다. 작은 시정수 값을 가지는 회로를 지나는 신호는 거의 루프 필터 출력 전압과 같은 값을 가진다. 큰 시정수 값을 가지는 회로를 지나는 신호는 루프 필터 출력전압의 평균값을 가지며, 비교기회로에서 기준 신호 역할을 한다. 비교기의 출력 신호는 루프 필터에 전류를 공급하는 보조 전하펌프를 제어한다. 루프 필터 출력 전압이 상승하면 보조 전하펌프는 루프 필터에서 전류를 방전시켜 루프 필터 출력 전압이 하강하게 하고, 또는 루프 필터 출력 전압이 하강하면 보조 전하펌프는 루프 필터에서 전류를 충전시켜 루프 필터 출력 전압이 상승하게 한다. 이런 부궤환 루프는 필터 출력 전압 변동 폭을 줄여서 지터 크기를 감소시켜준다.

• KIEE International Transactions on Electrophysics and Applications
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• 제4C권3호
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• pp.96-100
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• 2004

The Nd： YAG laser is commonly used throughout many fields such as accurate material processing, IC marking, semiconductor annealing, medical operation devices, etc., due to the fact that it has good thermal and mechanical properties and is easy to maintain. In materials processing, it is essential to vary the laser power density for specific materials. The laser power density can be mainly controlled by the current pulse width and pulse repetition rate. It is important to control the laser energy in those fields using a pulsed laser. In this paper we propose the constant-frequency current resonant half-bridge converter and monitoring of capacitor charging voltage. This laser power supply is designed and fabricated to have less switching loss, compact size, isolation with primary and secondary transformers, and detection of capacitor charging voltage. Also, the output stabilization characteristics of this Nd： YAG laser system are investigated. The test results are described as a function of laser output energy and flashlamp arc discharging constant. At the energy storage capacitor charges constant voltage, the laser output power is 2.3％ error range in 600[V].

• 전기학회논문지P
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• 제56권2호
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• pp.83-89
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• 2007

The LC filter design procedure of the inverter output filter is described. The transfer function of the filter output voltage to the load current is described with the capacitor value and the system time constant considering the system controller. By using the closed form of the relation between the filter capacitor value and the system time constant, the capacitor value can be calculated with the given system time constant and vice versa. It is more practical for the implementation of power and control circuit of inverter. And as the effect of the load current to the voltage distortion can be calculated from the closed form, it is possible to analyze the system how much the voltage waveform is distorted in case of the nonlinear load. All the proposed design procedure is verified with the simulation and experimental results.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 B
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• pp.1077-1079
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• 2000

In this paper. the design procedure of the inverter output filter is described. The transfer function of the filter output voltage to the load current is described with the capacitor value and the system time constant including the controller. This means that the relation between the filter capacitor value and the system time constant is given as the closed form. By using the above closed form. the capacitor value can be calculated with the system time constant which can be implemented practically not using the try and error method. And as the effect of the load current to the voltage distortion can be calculated from the closed form, it can be verified how much the voltage distortion is effected when the nonlinear load is connected.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 학술대회 논문집 전문대학교육위원
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• pp.206-211
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• 2005

The LC filter design procedure of the inverter output filter is described. The transfer function of the filter output voltage to the load current is described with the capacitor value and the system time constant considering the system controller. By using the closed form of the relation between the filter capacitor value and the system time constant, the capacitor value can be calculated with the given system time constant and vice versa. It is more practical for the implementation of power and control circuit of inverter. And as the effect of the load current to the voltage distortion can be calculated from the closed form, it is possible to analyze the system how much the voltage waveform is distorted in case of the nonlinear load. All the proposed design procedure is verified with the simulation and experimental results.